This application claims priority to Korean Patent Application 2002-0059555, filed on Sep. 30, 2002, the contents of which are herein incorporated by reference in their entirety.
The present invention relates to apparatus for drying wafers, and more particularly, to spin type drying apparatus and methods for using the same.
The integration density, speed and reliability for integrated circuit (semiconductor) devices continues to increase to meet the demands for higher performance products incorporating such integrated circuit devices. As the performance requirements of the integrated circuit devices increase, the demands on manufacturing processes to provide a desirable yield when fabricating such devices may also increase.
The manufacture of semiconductor devices generally includes repeated execution of various individual processing steps, such as a deposition process, a photolithography process, an etching process, a polishing process, a cleaning process, a drying process and so on. The various processes may be repeated in a desired sequence with specified materials to provide a layered structure with the desired characteristics as will be understood by those of skill in the art. In particular, the cleaning process is typically used to remove impurities attached to the surface of a wafer or undesired films formed on the wafer during the other processing operations. The importance of the cleaning process generally increases with higher density and more complicated fabrication patterns for the integrated circuit devices and as the aspect ratios of the patterns increase. The drying process is intended to remove moisture remaining on the wafer from the surface of the wafer after cleaning. However, watermarks may be left on the surface of the wafer after the cleaning and drying process. Such watermarks may cause processing failures during subsequent manufacturing process steps.
Wafer drying apparatus may be divided into batch type wafer drying apparatus and a single type rapid wafer drying apparatus, such as spin type drying apparatus. The batch type wafer drying apparatus can be further divided into a single container type apparatus and a dual container type apparatus. The single container type apparatus generally includes one container in which a wafer is rinsed and dried. Various single container type apparatus dry the wafer by employing, for example, the Marangoni effect or a spray of isopropyl alcohol. In contrast, a dual container type wafer drying apparatus generally has two containers, one for rinsing the wafer and the other for drying the wafer. Typically, for the dual container type wafer drying apparatus, the final rinsing process for the wafer is executed in a lower container and the drying process is performed in an upper container after the wafer is lifted into the upper container from the lower container. The dual container type wafer drying apparatus can dry the wafer using, for example, the Marangoni effect, spray of a liquid isopropyl alcohol, or using vapor of an isopropyl alcohol.
Examples of a batch type wafer drying apparatus are described in U.S. Pat. No. 6,027,574 to Fishkin et al. and U.S. Pat. No. 6,029,371 to Kamikawa et al. Fishkin et al. describes a batch type wafer drying apparatus of the single container type that employs the Marangoni effect. Kamikawa et al. discloses a batch type wafer drying apparatus that uses an isopropyl alcohol vapor.
A single type rapid wafer drying apparatus can dry a wafer using the centrifugal force produced during rotation of the wafer at a high speed, such as with a spin type drying apparatus. While the wafer is being rotated, an organic solvent, such as isopropyl alcohol, can be delivered onto a surface of the wafer to improve the efficiency of the wafer drying process.
An example of a single type rapid wafer drying apparatus is disclosed in U.S. Pat. No. 5,289,156 to Shibasaki et al. Shibasaki et al. describes a rotary (or spin type) wafer drying apparatus including a holder horizontally gripping a wafer and defining a back space positioned under the rear face of the wafer. A driving part rotates the wafer and a gas supply member provides a clean gas to the back space.
A spin type rapid wafer drying apparatus generally dries the wafer utilizing the centrifugal force generated by the rotation of the wafer. The apparatus may provide isopropyl alcohol to the wafer in order to increase the effectiveness of the removal of moisture from the wafer. The isopropyl alcohol can be delivered to the wafer, for example, in a vapor phase and/or in a mist state with a carrier gas.
FIG. 1 is a cross-sectional view illustrating a conventional single type rapid (spin type) wafer drying apparatus. As shown in FIG. 1, a wafer W is horizontally supported on rotating chuck 110. The wafer is held on the rotating chuck 110 by a vacuum provided through the rotating chuck 110. A rotary shaft 112 connects a driving part (e.g., motor) 114 to a bottom portion of the rotating chuck 110 to spin the rotating chuck 110 during the cleaning/drying operations. A cover 116 is disposed around the rotating chuck 110 to control the escape of de-ionized water dispersed from the wafer W during the cleaning operation. As shown in FIG. 1, the cover 116 has a cup shape with an open upper face and the rotary shaft 112 passes through the bottom portion of the cover 116. The rotary shaft 112 defines the central axis of rotation of the rotary chuck 110.
A de-ionized water supply member 120 is also shown in FIG. 1 disposed over the wafer W. In addition, an isopropyl alcohol supply member 130 is disposed over the wafer W. The de-ionized water supply member 120 moves from the central portion of the wafer W to the edge portion of the wafer W while supplying the de-ionized water onto the wafer W. The isopropyl alcohol supply member 130, like the de-ionized water supply member, also moves from the central portion to the edge portion of the wafer W during cleaning and supplies an isopropyl alcohol onto the wafer W. The isopropyl alcohol is provided to reduce the surface tension of the de-ionized water on the wafer W so that the wafer W may be more efficiently dried due to the centrifugal force generated by rotation of the wafer W.
Various problems may result when using the above-described apparatus 100. For example, watermarks may occur at the edge portion of the wafer W as the de-ionized water supply member 120 scanning the surface of the wafer W may not supply sufficient de-ionized water onto the edge portion of the wafer W. When the de-ionized water supply member 120 is positioned over the central portion of the wafer W, the moisture at the edge portion of the wafer W may not be properly removed from the wafer W and may, instead, be naturally dried (as contrasted with removed by centrifugal force) at the edge portion of the wafer W. Watermarks generally result when there is naturally dried moisture at the edge portion of the wafer W.
In addition, the de-ionized water dispersed from the wafer W due to centrifugal force may strike and rebound from the cover 116. As a result, this de-ionized water may fall back onto an already dried portion of the wafer W, generally the central portion. This re-deposited de-ionized water may also not be properly removed and may form additional watermarks on the wafer W. If the spin speed of the wafer W and the scanning speeds of the de-ionized water and the isopropyl alcohol supply members 120 and 130 are reduced to improve the efficiency of the drying process, the time required to dry the wafer W would be expected to increase.
The problems described above generally increase in seriousness as the size of the wafer W increases. However, as a result of potential benefits of working with larger wafer sizes, various manufacturing processes are tending to use larger wafer sizes, thereby increasing the potential benefits of improved wafer drying.
In some embodiments of the present invention, an apparatus for drying a wafer includes a rotating chuck configured to rotate the wafer. An organic solvent supply member is positioned adjacent a face of the wafer. The organic solvent supply member has a plurality of solvent supply nozzles disposed to supply an organic solvent(s) onto the wafer.
In particular embodiments of the present invention, the apparatus further includes a movable de-ionized water supply member positioned adjacent the face of the wafer. The de-ionized water supply member is configured to supply de-ionized water onto the wafer and to move radially between a position adjacent a central portion of the wafer and an edge portion of the wafer. The organic solvent supply member includes a first solvent supply member including at least one of the solvent supply nozzles positioned adjacent the wafer so as to move radially between a position adjacent the central portion of the wafer and the edge portion of the wafer. A second organic solvent supply member, including at least one of the solvent supply nozzles, is positioned in a fixed location adjacent the central portion. The de-ionized water supply member and the first organic solvent supply member may be configured to move together.
The solvent may be an alcohol. The solvent may include a vapor phase and at least one of the first and second solvent supply members may be configured to supply a vapor phase solvent. The solvent may include a mist phase solvent carried by a carrier gas and at least one of the first and second solvent supply members may be configured to supply the mist phase solvent carried by a carrier gas.
In other embodiments of the present invention, the apparatus includes a drying gas supply member positioned adjacent the wafer that is configured to supply a drying gas to the wafer. The de-ionized water supply member may be a longitudinally extending member extending radially from the central portion that includes a plurality of de-ionized water supply nozzles. The de-ionized water supply member may extend over the edge portion of the wafer when the de-ionized water supply member is in the position adjacent the central portion of the wafer.
In further embodiments of the present invention, the first solvent supply member is an arcuate shaped member including a plurality of nozzles. The arcuate shaped portion is concave with reference to a central axis of the rotary chuck. The de-ionized water supply member may also be an arcuate shaped member including a plurality of nozzles, the arcuate shaped portion being concave with reference to a central axis of the rotary chuck. The first organic solvent supply member may be positioned between the de-ionized water supply member and the central axis of the rotary chuck.
In other embodiments of the present invention, the de-ionized water supply member includes a first arcuate member and a second arcuate member, each including a plurality of nozzles, the second arcuate member being positioned on an opposite side of the central axis of the rotary chuck from the first arcuate member and being movable in an opposite direction from the first arcuate member. The first organic solvent supply member may include a third arcuate member and a fourth arcuate member, each including a plurality of nozzles, the fourth arcuate member being positioned on an opposite side of the central axis of the rotary chuck from the third arcuate member and being movable in an opposite direction from the third arcuate member. The first and second arcuate member may define a substantially circular member when the de-ionized water supply member is in the position adjacent the central portion of the wafer and the third and fourth arcuate member may define a substantially circular member when the first organic solvent supply member is in the position adjacent the central portion of the wafer.
In further embodiments of the present invention, the rotary chuck is configured to hold the wafer in a horizontal plane and the organic solvent supply member is a longitudinally extending member extending from a central portion of the wafer to an edge portion of the wafer. The plurality of nozzles are positioned therein in radially extending positions. The solvent supply member is positioned over the wafer. The organic solvent supply member may have a length of about half a diameter of the wafer. Alternatively, the organic solvent supply member may have a length of about a diameter of the wafer. The organic solvent supply member may be a pipe shaped member having a receiving chamber configured to receive the organic solvent and the nozzles of the organic solvent supply member may be communicatively coupled to the receiving chamber.
In other embodiments of the present invention, the rotary chuck is configured to hold the wafer in a horizontal plane. The organic solvent supply member is a substantially disc shaped member extending over substantially the entire wafer. The plurality of nozzles is positioned therein to substantially uniformly supply the organic solvent to the wafer without movement of the organic solvent supply member. The organic solvent supply member may further include a receiving chamber configured to receive the organic solvent and the nozzles of the organic solvent supply member may be communicatively coupled to the receiving chamber.
In further embodiments of the present invention, methods are provided of spin drying a wafer using a drying apparatus having a plurality of organic solvent supply members. A first of the organic solvent supply members is provided that directs organic solvent towards the wafer and a de-ionized water supply member is provided that directs de-ionized water toward the wafer. The first of the organic solvent supply members and the de-ionized water supply member are movable radially across the wafer. A second of the organic solvent supply members is provided in a fixed position adjacent a central portion of the wafer that directs organic solvent toward the wafer. Organic solvent is provided to the first and second organic solvent supply members and de-ionized water is provided to the de-ionized water supply member while rotating the wafer and moving the first organic solvent supply member and the de-ionized water supply member radially across the wafer to dry the wafer.
Further embodiments of the present invention provide an apparatus for drying a wafer having a rotating chuck, a de-ionized water supply member for supplying de-ionized water onto the wafer, a first organic solvent supply member for supplying an organic solvent onto the wafer on which the de-ionized water is supplied, and a second organic solvent supply member for supplying an organic solvent onto a central portion of the wafer.
The rotating chuck horizontally grips the wafer and rotates the wafer. The de-ionized water supply member is disposed over the wafer rotated by the rotating chuck and the de-ionized water supply member moves from the central portion of the wafer to the edge portion of the wafer. The first organic solvent supply member moves along a moving passage of the de-ionized water supply member.
Other embodiments of the present invention provide an apparatus for drying a wafer that includes a rotating chuck, a de-ionized water supply member having a plurality of de-ionized water supply nozzles disposed along a central axis of the de-ionized water supply member for supplying de-ionized water onto the wafer, and an organic solvent supply member for supplying an organic solvent onto the wafer on which the de-ionized water is supplied.
The rotating chuck horizontally grips a wafer and rotates the wafer. The de-ionized water supply member is disposed over the wafer rotated by the rotating chuck. The de-ionized water supply member has a pipe shape prolonged from a central portion of the wafer to an edge portion of the wafer and the water supply member moves from the central portion of the wafer to the edge portion of the wafer. The organic solvent supply member moves along a moving passage of the de-ionized water supply member.
Further embodiments of the present invention provide an apparatus for drying a wafer that has a rotating chuck for horizontally gripping a wafer and for rotating the wafer, a de-ionized water supply member for supplying de-ionized water onto the wafer and an organic solvent supply member having a plurality of organic solvent supply nozzles for supplying an organic solvent onto the wafer on which the de-ionized water is supplied. The de-ionized water supply member is disposed over the wafer rotated by the rotating chuck and the water supply member moves from a central portion of the wafer to an edge portion of the wafer. The organic solvent supply member has a curved pipe shape and the organic solvent supply member is disposed over the wafer so that a first curved center of the organic solvent supply member faces a center of the wafer. The organic solvent supply member moves along a moving passage of the de-ionized water supply member.
Other embodiments of the present invention provide an apparatus for drying a wafer that includes a rotating chuck for horizontally gripping a wafer and for rotating the wafer and an organic solvent supply member having a plurality of organic solvent supply nozzles radially disposed over the wafer for supplying an organic solvent onto the wafer. The organic solvent supply member is disposed over the wafer rotated by the rotating chuck. The organic solvent can include an isopropyl alcohol, and may include the vapor of the isopropyl alcohol or the mist of the isopropyl alcohol.